DAYBUE Oral solution Ref.[107361] Active ingredients: Trofinetide

5.1 Diarrhea

In Study 1 [see Clinical Studies (14)] and in long-term studies, 85% of patients treated with DAYBUE experienced diarrhea. In those treated with DAYBUE, 49% either had persistent diarrhea or recurrence after resolution despite dose interruptions, reductions, or concomitant antidiarrheal therapy. Diarrhea severity was of mild or moderate severity in 96% of cases. In Study 1, antidiarrheal medication was used in 51% of patients treated with DAYBUE.

Advise patients to stop laxatives before starting DAYBUE. If diarrhea occurs, patients should notify their healthcare provider, consider starting antidiarrheal treatment, and monitor hydration status and increase oral fluids, if needed. Interrupt, reduce dose, or discontinue DAYBUE if severe diarrhea occurs or if dehydration is suspected [see Dosage and Administration (2.4)].

5.2 Weight Loss

In Study 1, 12% of patients treated with DAYBUE experienced weight loss of greater than 7% from baseline, compared to 4% of patients who received placebo. In long-term studies, 2.2% of patients discontinued treatment with DAYBUE due to weight loss.

Monitor weight and interrupt, reduce dose, or discontinue DAYBUE if significant weight loss occurs.

The following clinically significant adverse reactions are described elsewhere in labeling:

• Diarrhea [see Warnings and Precautions (5.1)]
• Weight Loss [see Warnings and Precautions (5.2)]

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In controlled and uncontrolled trials in patients with Rett syndrome, 260 patients ages 2 to 40 years were treated with DAYBUE, including 109 patients treated for more than 6 months, 69 patients treated for more than 1 year, and 4 patients treated for more than 2 years.

Adult and Pediatric Patients With Rett Syndrome 5 Years of Age and Older

The safety of DAYBUE was evaluated in a randomized, double-blind, placebo-controlled, 12-week study of patients with Rett syndrome (Study 1) [see Clinical Studies (14)]. In Study 1, 93 patients received DAYBUE and 94 patients received placebo. All patients were female, 92% were White, and the mean age was 11 years (range 5 to 20 years).

Adverse Reactions Leading to Discontinuation of Treatment

Eighteen patients (19%) receiving DAYBUE had adverse reactions that led to withdrawal from the study. The most common adverse reaction leading to discontinuation of treatment with DAYBUE was diarrhea (15%).

Common Adverse Reactions

Adverse reactions that occurred in Study 1 in at least 5% of patients treated with DAYBUE and were at least 2% more frequent than in patients on placebo are presented in Table 2.

Table 2. Adverse Reactions in at Least 5% of Patients Treated With DAYBUE and at Least 2% Greater than Placebo in Study 1:

Pediatric Patients With Rett Syndrome 2 to 4 Years of Age

In an open-label study in pediatric patients 2 to 4 years of age with Rett syndrome, a total of 13 patients received DAYBUE for at least 12 weeks and 9 patients received DAYBUE for at least 6 months. Adverse reactions in pediatric patients 2 to 4 years of age treated with DAYBUE were similar to those reported in adult and pediatric patients 5 years of age and older with Rett syndrome in Study 1.

7.1 Effect of DAYBUE on Other Drugs

Trofinetide is a weak CYP3A4 inhibitor; therefore, plasma concentrations of CYP3A4 substrates may be increased if given concomitantly with DAYBUE [see Clinical Pharmacology (12.3)]. Closely monitor when DAYBUE is used in combination with orally administered CYP3A4 sensitive substrates for which a small change in substrate plasma concentration may lead to serious toxicities.

Plasma concentrations of OATP1B1 and OATP1B3 substrates may be increased if given concomitantly with DAYBUE [see Clinical Pharmacology (12.3)]. Avoid the concomitant use of DAYBUE with OATP1B1 and OATP1B3 substrates for which a small change in substrate plasma concentration may lead to serious toxicities.

Risk Summary

There are no adequate data on the developmental risks associated with the use of DAYBUE in pregnant women. No adverse developmental effects were observed following oral administration of trofinetide to pregnant animals at doses associated with plasma exposures below those used clinically [see Animal Data].

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Data

Animal Data

Oral administration of trofinetide (0, 150, 450, or 1000 mg/kg twice daily; 0, 300, 900, or 2000 mg/kg/day) to pregnant rats during the period of organogenesis resulted in no adverse effects on embryofetal development. At the highest dose tested, plasma exposure (AUC) was less than that in humans at the maximum recommended human dose (MRHD) of 12,000 mg twice daily (24,000 mg/day).

Oral administration of trofinetide (0, 75, 150, or 300 mg/kg twice daily; 0, 150, 300, or 600 mg/kg/day) to pregnant rabbits during the period of organogenesis resulted in no adverse effects on embryofetal development. At the highest dose tested, plasma exposure (AUC) was less than that in humans at the MRHD.

Oral administration of trofinetide (0, 150, 450, or 1000 mg/kg twice daily; 0, 300, 900, or 2000 mg/kg/day) to rats throughout pregnancy and lactation resulted in no adverse effects on pre- and postnatal development. At the highest dose tested, plasma exposure (AUC) was less than that in humans at the MRHD.

Risk Summary

There is no information regarding the presence of trofinetide or its metabolites in human milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for DAYBUE and any potential adverse effects on the breastfed infant from DAYBUE or from the underlying maternal condition.

The safety and effectiveness of DAYBUE for the treatment of Rett syndrome have been established in pediatric patients aged 2 years and older. The safety and effectiveness of DAYBUE for the treatment of Rett syndrome in pediatric patients 5 years of age and older was established in a randomized, double-blind, placebo-controlled, 12-week study (Study 1), which included 108 pediatric patients age 5 to less than 12 years of age and 47 pediatric patients age 12 to less than 17 years of age [see Adverse Reactions (6.1) and Clinical Studies (14)]. Use of DAYBUE in patients 2 to 4 years of age is supported by evidence from Study 1 and pharmacokinetic and safety data in 13 pediatric patients 2 to 4 years of age treated with DAYBUE for 12 weeks [see Dosage and Administration (2.1), Adverse Reactions (6.1), Clinical Pharmacology (12.3), and Clinical Studies (14)].

Safety and effectiveness in pediatric patients less than 2 years of age have not been established.

Juvenile Animal Data

Oral administration of trofinetide (0, 150, 300, or 1000 mg/kg twice daily; 0, 300, 600, or 2000 mg/kg/day) to rats from postnatal day (PND) 13-14 through 28 weeks of age resulted in no adverse effects on growth or neurobehavioral function. Plasma exposures at the highest dose tested were similar to those in pediatric patients at recommended doses.

Oral administration of trofinetide (0, 150, 300, or 1000 mg/kg twice daily; 0, 300, 600, or 2000 mg/kg/day) to juvenile rats for 10 weeks beginning on PND 13-14 resulted in no adverse effects on sexual maturation or reproductive function. Plasma exposures at the highest dose tested were similar to those in pediatric patients at recommended doses.

Clinical studies of DAYBUE did not include patients 65 years of age and older to determine whether or not they respond differently from younger patients. This drug is known to be substantially excreted by the kidney. Because elderly patients are more likely to have decreased renal function, it may be useful to monitor renal function.

No dedicated clinical study has been conducted to evaluate the pharmacokinetics of DAYBUE in subjects with renal impairment. Since the drug is eliminated mainly through the kidney, administration of DAYBUE to patients with moderate or severe renal impairment is not recommended.